Taxation of Stock Options
Know when ISOs, NSOs, and ESPPs get taxed, the AMT trap, and how holding periods change the rate.
TL;DR
- Tax
NSOsas ordinary income on the spread at exercise. - Watch
ISOs: the exercise spread is an AMT item even before you sell. - Hold shares long enough to turn later gain into
longTermGains.
The Three Option Types
ISOEmployee-only options that can reach capital gains rates.
No regular tax at exercise (AMT may hit)NSOThe spread is ordinary income the moment you exercise.
Spread taxed as income at exerciseESPPA purchase plan; the discount is taxed when you sell.
Discount = ordinary income at saleNothing at GrantSimply receiving options is never a taxable event.
Grant = no taxISOs and AMT
Exercise SpreadMarket value minus strike is an AMT preference item.
(FMV - strike) x shares into AMTIQualifying HoldHold 1 year past exercise and 2 past grant for the low rate.
1 yr after exercise, 2 after grantThe AMT CreditAMT paid on an exercise can offset regular tax later.
Form 8801 credit carries forwardSpread the ExercisesExercising in batches keeps each year's spread small.
Stay under your AMT crossoverNSOs and ESPPs
Income at ExerciseThe NSO spread lands on your W-2 and is withheld on.
Spread in W-2 Box 1Reset Your BasisYour cost basis becomes the value at exercise.
Basis = FMV at exercise, not strikeThen Capital GainsGrowth after exercise is a short- or long-term gain.
Held over a year? Long-termESPP DiscountThe purchase discount is ordinary income at sale.
Often up to a 15% discountPlan Your Moves
Exercise ISOs EarlyAn early-year exercise gives room to hold for the year.
January exercise, meet 1-yr by year endModel the AMTRun Form 6251 before a large ISO exercise.
Know the AMT before you actMind Cost BasisReconcile Forms 3921 and 3922 with your broker.
Avoid double-counting the spreadCheck State RulesSome states do not honor ISO treatment.
State may tax it as incomeTips
- Get a mock tax projection before exercising a big block, since
AMTand capital gains interact in ways that are hard to eyeball. - After an
NSOexercise, set your cost basis to the fair market value, not the strike, so you are not taxed twice on the same spread.
Warnings
- Selling
ISOshares before one year past exercise and two past grant turns the bargain spread into ordinary income. - Exercising
ISOsand holding can trigger AMT on a paper gain, and if the stock later falls you paid tax on money you never got.
In Practice
Follow an NSO through exercise and sale to see where the tax lands, and where people overpay.
You hold NSOs with a $10 strike and exercise 1,000 shares when the stock trades at $50, then sell later at $70.
- Spread at exercise: ($50 - $10) x 1,000 = $40,000 ordinary income.
- That $40,000 goes on your W-2, with tax withheld.
- Your new cost basis is the $50 market value, not the $10 strike.
- Sale gain: ($70 - $50) x 1,000 = $20,000 capital gain.
You are taxed on $40,000 now and only $20,000 more at sale.
Use the exercise value as your basis, or you will be taxed twice on the spread.
FAQ
Incentive stock options (ISOs) go only to employees and can reach long-term capital gains rates if you meet the holding periods, though the exercise spread may trigger AMT. Non-qualified options (NSOs) can go to anyone, and the spread at exercise is always taxed as ordinary income with payroll withholding.
Never at grant. For an NSO, the spread between strike and market value is ordinary income at exercise, and later growth is a capital gain at sale. For an ISO, exercise usually has no regular tax but feeds AMT, and the whole gain can be long-term if you hold long enough before selling.
The spread between your strike price and the market value at exercise is added to income for AMT purposes, even though regular tax ignores it until you sell. A large exercise can push your tentative minimum tax above your regular tax, so the difference is due as AMT. Model it on Form 6251 first.
Selling ISO shares before holding them at least one year after exercise and two years after grant. It disqualifies the shares from ISO treatment, so the bargain spread becomes ordinary income taxed at your regular rate instead of the lower long-term capital gains rate. Sometimes it is still the right move, but know the cost.